Cardiovascular function is altered as a process of aging. To assess the effect of age on left ventricular function, we studied 66 normal volunteers (age 21-77) by radionuclide angiography. All subjects had normal physical exams, blood pressures, electrocardiograms, and echocardiograms. The resting ejection fraction did not vary with age, but the increase in ejection fraction during maximal supine exercise declined linearly as a function of age. Although systolic function was unrelated to age, left ventricular diastolic filling declined with age, which was associated with an age-related increase in regional left ventricular diastolic asynchrony. Thus, aging does not affect left ventricular systolic function at rest but significantly influences left ventricular diastolic function at rest as well as the ejection fraction response during maximum exercise.